Electrical engineering may include
electronic engineering. Where a distinction is made, usually outside of the United States, electrical engineering is considered to deal with the problems associated with large-scale electrical systems such as
power transmission and
motor control, whereas electronic engineering deals with the study of small-scale electronic systems including
computers and
integrated circuits.
[1] Alternatively, electrical engineers are usually concerned with using electricity to transmit
energy, while electronic engineers are concerned with using electricity to process information. More recently, the distinction has become blurred by the growth of
power electronics.
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The discoveries of
Michael Faraday formed the foundation of electric motor technology.
Electricity has been a subject of scientific interest since at least the early 17th century. The first electrical engineer was probably
William Gilbert who designed the
versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity.
[2] In 1775,
Alessandro Volta's scientific experimentations devised the
electrophorus, a device that produced a static electric charge and, by 1800, Volta developed the voltaic pile, a forerunner of the electric battery.
[3] The
Society of Telegraph Engineers (the forerunner of the Institution of Electrical Engineers, now the Institution of Engineering and Technology) was formed in 1871. This date is preserved by the telephone number of the IET's switchboard at its Savoy Place headquarters being currently 0207 240 1871.
Thomas Edison built the world's first large-scale electrical supply network.
Nikola Tesla made long-distance electrical transmission networks possible.
During this period, the work concerning electrical engineering increased dramatically. In 1882,
Edison switched on the world's first large-scale electrical supply network that provided 110 volts
direct current to fifty-nine customers in lower Manhattan. In 1884,
Sir Charles Parsons invented the
steam turbine which today generates about 80 percent of the
electric power in the world using a variety of heat sources. In 1887,
Nikola Teslafiled a number of patents related to a competing form of power distribution known as
alternating current. In the following years, a bitter rivalry between Tesla and Edison, known as the "
War of Currents", took place over the preferred method of distribution. AC eventually replaced DC for generation and power distribution, enormously extending the range and improving the safety and efficiency of power distribution.
The efforts of the two did much to further electrical engineering—Tesla's work on
induction motors and
polyphase systems influenced the field for years to come, while Edison's work on telegraphy and his development of the
stock ticker proved lucrative for his company, which ultimately became
General Electric. However, by the end of the 19th century, other key figures in the progress of electrical engineering were beginning to emerge.
[8]Modern developments
During the
development of radio, many scientists and
inventors contributed to
radio technology and electronics. In his classic
UHF experiments of 1888,
Heinrich Hertz transmitted (via a
spark-gap transmitter) and detected
radio waves using electrical equipment. In 1895, Nikola Tesla was able to detect signals from the transmissions of his New York lab at West Point (a distance of 80.4 km / 49.95 miles).
[9] In 1897,
Karl Ferdinand Braun introduced the
cathode ray tube as part of an
oscilloscope, a crucial enabling technology for
electronic television.
[10] John Fleming invented the first radio tube, the
diode, in 1904. Two years later,
Robert von Lieben and
Lee De Forest independently developed the amplifier tube, called the
triode.
[11] In 1895,
Guglielmo Marconi furthered the art of hertzian wireless methods. Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by the curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of 2,100 miles (3,400 km).
[12] In 1920,
Albert Hull developed the
magnetron which would eventually lead to the development of the
microwave oven in 1946 by
Percy Spencer.
[13][14] In 1934, the British military began to make strides toward
radar (which also used the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at
Bawdsey in August 1936.
[15]The invention of the
transistor in 1947 by
William B. Shockley,
John Bardeen and
Walter Brattain opened the door for more compact devices and led to the development of the
integrated circuit in 1958 by
Jack Kilbyand, independently in 1959, by
Robert Noyce.
[18] Starting in 1968,
Ted Hoff and a team at
Intel invented the first commercial
microprocessor, which presaged the
personal computer. The
Intel 4004 was a 4-bit processor released in 1971 but, in 1973, the
Intel 8080, an 8-bit processor, made the first personal computer, the
Altair 8800, possible.
[19]Education
Practising engineers
In most countries, a Bachelor's degree in engineering represents the first step towards
professional certification and the degree program itself is certified by a
professional body. After completing a certified degree program the engineer must satisfy a range of requirements (including work experience requirements) before being certified. Once certified, the engineer is designated the title of
Professional Engineer (in the United States, Canada and South Africa ),
Chartered Engineer (in the United Kingdom, Hong Kong, India, Ireland and
Zimbabwe), Chartered Professional Engineer (in Australia and New Zealand) or
European Engineer (in much of the
European Union).
The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may seal engineering work for public and private clients".
[21] This requirement is enforced by state and provincial legislation such as
Quebec's Engineers Act.
[22] In other countries, no such legislation exists. Practically all certifying bodies maintain a
code of ethics that they expect all members to abide by or risk expulsion.
[23] In this way these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to
contract law. In cases where an engineer's work fails he or she may be subject to the
tort of negligence and, in extreme cases, the charge of
criminal negligence. An engineer's work must also comply with numerous other rules and regulations such as
building codes and legislation pertaining to
environmental law.
Professional bodies of note for electrical engineers include the
Institution of Engineering and Technology (IET) and the
Institute of Electrical and Electronics Engineers (IEEE). The IET publishes 21 journals, has a worldwide membership of over 150,000, and claims to be the largest professional engineering society in Europe.
[24][25] The IEEE claims to produce 30% of the world's literature in electrical engineering, has over 360,000 members worldwide and holds over 3,000 conferences annually.
[26] Obsolescence of technical skills is a serious concern for electrical engineers. Membership and participation in technical societies, regular reviews of periodicals in the field and a habit of continued learning are therefore essential to maintaining proficiency.
[27]In Australia, Canada and the United States, electrical engineers make up around 0.25% of the labour force (see
note). Outside of Europe and North America, engineering graduates per-capita, and hence probably electrical engineering graduates also, are most numerous in Taiwan, Japan and South Korea.
[28]Tools and work
Fundamental to the discipline are the sciences of
physics and
mathematics as these help to obtain both a
qualitative and
quantitative description of how such systems will work. Today most
engineering work involves the use of
computers and it is commonplace to use
computer-aided design programs when designing electrical systems. Nevertheless, the ability to sketch ideas is still invaluable for quickly communicating with others.
For many engineers, technical work accounts for only a fraction of the work they do. A lot of time may also be spent on tasks such as discussing proposals with clients, preparing
budgets and determining
project schedules.
[30] Many senior engineers manage a team of
technicians or other engineers and for this reason
project managementskills are important. Most engineering projects involve some form of documentation and
strong written communication skills are therefore very important.
Sub-disciplines
Electrical engineering has many sub-disciplines, the most popular of which are listed below. Although there are electrical engineers who focus exclusively on one of these sub-disciplines, many deal with a combination of them. Sometimes certain fields, such as electronic engineering and computer engineering, are considered separate disciplines in their own right.
Power
Power engineering deals with the
generation,
transmission and
distribution of
electricity as well as the design of a range of related devices. These include
transformers,
electric generators,
electric motors, high voltage engineering and
power electronics. In many regions of the world, governments maintain an electrical network called a
power grid that connects a variety of generators together with users of their energy. Users purchase electrical energy from the grid, avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it. Such systems are called
on-grid power systems and may supply the grid with additional power, draw power from the grid or do both. Power engineers may also work on systems that do not connect to the grid, called
off-grid power systems, which in some cases are preferable to on-grid systems. The future includes Satellite controlled power systems, with feedback in real time to prevent power surges and prevent blackouts.
Control
Electronics
Prior to the second world war, the subject was commonly known as
radio engineering and basically was restricted to aspects of communications and
radar,
commercial radio and
early television. Later, in post war years, as consumer devices began to be developed, the field grew to include modern television, audio systems,
computers and
microprocessors. In the mid to late 1950s, the term
radio engineering gradually gave way to the name
electronic engineering.
Before the invention of the
integrated circuit in 1959, electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and
power and were limited in speed, although they are still common in some applications. By contrast,
integrated circuits packed a large number—often millions—of tiny electrical components, mainly
transistors, into a small chip around the size of a
coin. This allowed for the powerful
computers and other electronic devices we see today.
Microelectronics
Microelectronic components are created by chemically fabricating wafers of semiconductors such as silicon (at higher frequencies,
compound semiconductors like gallium arsenide and indium phosphide) to obtain the desired transport of electronic charge and control of current. The field of microelectronics involves a significant amount of chemistry and material science and requires the electronic engineer working in the field to have a very good working knowledge of the effects of
quantum mechanics.
Signal processing
A
Bayer filter on a
CCD requires signal processing to get a red, green, and blue value at each pixel.
Signal Processing is a very mathematically oriented and intensive area forming the core of
digital signal processing and it is rapidly expanding with new applications in every field of electrical engineering such as communications, control, radar, TV/Audio/Video engineering, power electronics and bio-medical engineering as many already existing analogue systems are replaced with their digital counterparts.
Although in the classical era,
analogue signal processing only provided a mathematical description of a system to be designed, which is actually implemented by the analogue hardware engineers, Digital Signal Processing both provides a mathematical description of the systems to be designed and also actually implements them (either by software programming or by hardware embedding) without much dependency on hardware issues, which exponentiates the importance and success of DSP engineering.
The deep and strong relations between signals and the information they carry makes signal processing equivalent of information processing. Which is the reason why the field finds so many diversified applications. DSP processor ICs are found in every type of modern electronic systems and products including,
SDTV |
HDTV sets, radios and mobile communication devices,
Hi-Fi audio equipments,
Dolby noise reduction algorithms,
GSM mobile phones,
mp3 multimedia players, camcorders and digital cameras, automobile control systems,
noise cancelling headphones, digital
spectrum analyzers, intelligent missile guidance,
radar,
GPS based cruise control systems and all kinds of
image processing,
video processing,
audio processing and
speech processing systems.
Telecommunications
Once the transmission characteristics of a system are determined, telecommunication engineers design the
transmitters and
receivers needed for such systems. These two are sometimes combined to form a two-way communication device known as a
transceiver. A key consideration in the design of transmitters is their
power consumption as this is closely related to their
signal strength. If the signal strength of a transmitter is insufficient the signal's information will be corrupted by
noise.
